The immune response to the hIDUA protein is consistent with the relatively high immunogenicity of this protein and has been previously observed in murine, canine, and feline models of gene therapy, in addition to the high rate of antibody responses in MPS I patients treated with recombinant IDUA.12, 13, 14, 18 Irrespective of the mechanism of DRG toxicity, the findings suggest that these cells were heavily transduced following ICM AAV9 administration. This evidence concerns the gene IDUA and Scheie syndrome.